Container handling fork lift mechanism



Nov. 16', 1965 -c. E- MKEON 3 CONTAINER HANDLING FORK LIFT MECHANISM Filed Nov. 13. 1961 4 Sheets-Sheet 1 CHNRAIG A. MAtG/V INVENTOR.

ATT R Nov. 16, 1965 c. E. M KEON 3,217,912

CONTAINER HANDLING FORK LIFT MECHANISM Filed Nov. 13. 1961 4 Sheets-Sheet 2 ATTOIQ'A/EY 4 Sheets-Sheet 3 I NVENTOR.

cum/was .6. AMA 50M A rTOe/VEY C- E. M KEON CONTAINER HANDLING FORK LIFT MECHANISM Nov. 16, 1965 Filed Nov. 13, 1961 Nov. 16, 1965 c, E. MOKEON Filed Nov. 13, 1961 CONTAINER HANDLING FORK LIFT MECHANISM 4 Sheets-Sheet 4 United States Patent 3,217,912 CONTAINER HANDLING FORK LIFT MECHANISM Charles E. McKeon, Birmingham, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Filed Nov. 13, 1961, Ser. No. 151,852 4 Claims. (Cl. 214-300) This invention relates to materials handling devices, and more particularly to a bottom-dump container and forktype lifting device therefor.

It is customary to provide pallets and containers in which a space is provided at the bottom for receiving lifting forks of a fork lift truck. Mechanisms have been developed for dumping such containers by tilting the containers to pour the contents therefrom, but dumping in this manner requires a strong container and may tend to damage the contents.

According to the present invention, a bottom-dump container suitable for receiving lifting forks of a fork lift device is provided. The forks of the fork lift each are rotatable on an axis extending longitudinally thereof and located adjacent to their outside surface in a manner to open the bottom of the container, but are normally held in the conventional position to permit raising a load and carrying it in the usual manner. At the will of the operator, the forks may be rotated when the load is a short distance off of the floor to open the bottom of the container and dump the contents.

Among the objects of the present invention are to provide an improved lifting fork attachment for fork lift trucks and other equipment, to provide for rotation of the forks for bottom dumping of a container, to provide an improved container adapted for use with said forks to facilitate bottom dumping, to provide a container and lifting fork attachment that is simple and durable in construction and dependable in use, and generally to improve devices of the type described.

Other objects, and objects relating to details and economies of construction and use, will be apparent from the detailed description to follow.

My invention is clearly defined in the appended claims, in the claims, as Well as in the description, parts may at times be identified by specific names for clarity and convenience, but such nomenclature is to be understood as having the broadest means consistent with the context and with the concept of my invention as distinguished from the pertinent prior art. The best form in which I have contemplated applying my invention is illustrated in the r accompanying drawings forming part of this specification, in which:

FIGURE 1 is a side elevation of a tractor-mounted fork lift and container embodying the present invention, a portion of the tractor being broken away for convenience of illustration.

FIGURE 2 is a front elevation of a fork lift carriage, lifting forks and associated mechanism. for rotating the forks, a portion of the fork lift mast being shown. The lifting forks and fork-rotating mechanism are shown in full line position with the forks horizontal, and in broken line position with the forks rotated downwardly.

FIGURE 3 is a view similar to FIGURE 2, a pallet and "ice container being shown supported on the forks and the container, pallet and forks being shown in vertical section. The pallet and container are shown in closed position.

FIGURE 4 is a View similar to FIGURE 3, the pallet and lifting forks being shown swung to partly open position and only the lower portion of the container and forkrotating mechanism being shown.

FIGURE 5 is an enlarged side elevation of a fork, the carriage and the fork-rotating mechanism, a portion of the mast being shown.

FIGURE 6 is a fragmentary section taken generally along the line 66 of FIGURE 2, the fork being shown in horizontal position.

FIGURE 7 is a fragmentary side elevation indicated by the line 77 of FIGURE 2, the fork being shown in downwardly-rotated position.

FIGURE 8 is a top plan view of the pallet and container of FIGURES 1 and 3, most of the container being broken away.

FIGURE 9 is a perspective view of two sides and the bottom of an alternative container for use with the fork lifting device of the present invention.

The device of the present invention is shown incorporated in a tractor-mounted fork lift, although the device may be incorporated in other lifting devices, including tractor-mounted loaders and may be applied to powerliftable draft links of a tractor.

Referring now to the drawings, FIGURE 1 shows a tractor 10 on which is mounted a hydraulically actuated fork lift mast 11. In applying fork lift masts to tractors, it is usual to mount the mast on the rear of the tractor and to reverse the operating position and. controls of the tractor, as generally indicated in the drawings.

A carriage 12 is mounted on the mast 11 for generally vertical movement along the length of the mast. The carriage includes a face plate 14 extending horizontally and receiving a pair of vertically extending side members 15 and 16 for receiving the lifting forks. Movement of the carriage 12 along the mast is controlled by a hydraulic cylinder 17 extending along the center line of the mast and lifting chains 18 extending longitudinally of the mast and connected with the carriage in order to raise the carriage and permit it to be lowered as desired along the mast. The mast construction is more or less conventional in tractormounted fork lifts and does not comprise a part of the present invention.

According to the present invention, a pair of lifting forks 19 and 20 project generally horizontally from the face plate 14, the lifting forks being similar but of opposite hand and being mounted on the face plate by means of the members 15 and 16 for rotation of the lifting forks from a generally horizontal plane into a downwardly extending position.

Referring now to FIGURES 2, 5 and 7, the lifting fork 20 is provided at its inner end with a pair of spaced brackets 21 and 22 which project a short distance laterally beyond the outside surface 24 of the fork 20. The brackets 21 and 22 of the lifting fork 20 cooperate with a pair of spaced brackets 25 and 26 mounted on the lower end of the side member 16 of the carriage, a pin 27 extending through holes in the brackets so as to form an axis for rotation of the lifting fork which extends longitudinally of the fork and is located a short distance beyond the outside surface 24 of the fork, and preferably also a slight distance above the upper surface 29 of the fork.

In a similar construction but of opposite hand, the lifting fork 19 is mounted for swinging movement on the face plate 14 of the carriage 12 by means of spaced brackets mounted on the inner end of the fork 19 and spaced brackets mounted on the lower end of the side member 15, one bracket 30 on the fork and one bracket 31 on the side member being shown. The brackets are united by a pin 32 forming an axis for rotation of the fork 19. The pin 32 also is mounted a short distance laterally beyond the outside surface of the fork 19 and preferably a short distance above its upper surface.

The lifting forks 19 and 20 pivot about the pivot pins .32 and 27 to permit the forks to rotate from generally horizontal position, shown in full line in FIGURE 2, to downwardly extending vertical position, shown in broken line in that figure. The lifting forks are rotated between these two positions by a mechanism including a hydraulic cylinder 34 which is supported on the face plate 14 by a strap 35 bolted to the face plate. The lower end of the cylinder is connected by a pin 36 to a strut 37 bolted to the mast.

The upper end of the piston rod 39 of the hydraulic cylinder 34 is connected by a pin 40 to a yoke 41 extending transversely of the mast. A pair of links 42 connect .the ends of the yoke 41 with the brackets 21 and 30 of the lifting forks. The hydraulic cylinder 34 is preferably double acting, and a pair of hoses 44 extend from the opposite ends of the cylinder to a source of hydraulic fluid under pressure on the tractor (not shown). Thus, the operator may, by actuating a valve on the tractor (not shown), swing the lifting forks 19 and between horizontal and downwardly extending position or stop the forks intermediate those positions.

The fork lift device of the present invention is adapted to be used with a bottom dump container which preferably includes a split pallet. The split pallet 45, shown in plan view in FIGURE 8, consists of two pallet halves lying in a common plane and having spaced upper and lower boards or members 47 and 49 adapted to receive the lifting forks 19 and 20 therebetween. The pallet halves 46 are interconnected by a rectangular metal frame '50 extending around the periphery of the pallet and connected at intervals along the outside longer edges 51 of the pallets by a series of spaced straps 52 permitting pivoting of the pallet halves on the frame. Preferably, the frame is formed of a round steel rod one-half inch in diameter and is located adjacent the intersection of the top and outside surfaces of the pallet halves.

The proportioning of the split pallet 45 is such that upon the pallet being lifted by the lifting forks 19 and 20, the opposite sides of the frame 50 to which the pallet 'halves are hinged coincide generally with the axis of the pins 27 and 32..

Each pallet half is provided with a retainer 54 mounted on the upper surface of the pallet half and spaced inwardly a short distance from the outside edge of the pallet half (see FIGURE 8). The retainers extend only lengthwise of the pallet halves, and are spaced inwardly slightly from the axis defined by the mounting of the pallet halves on the opposite sides of frame 50. Retainers 54 are slightly spaced from the top surface of the pallet halves to form an outwardly opening slot.

The pallet 45 is adapted for use with a corrugated, paperboard carton or container 55 having a length and :width conforming to the dimensions of the rectangular frame 50. The bottom of the carton is open except for opposite marginal flaps 56 which may be inserted under the retainers 54, the pallet halves, together with the con- 4 tainer 55, making a bottom opening box. If desired, relatively short flaps 57 may be provided on the other two sides of the container 55, but these flaps are not fastened to the pallet.

The split pallet 45 with container 55 attached may be handled in the ordinary way, loaded, stacked and transported by the ordinary fork lift truck or by the fork lift device of the present invention with the lifting forks 19 and 2t maintained in horizontal position. When it is desired to dump the contents of the container, the pallet and container may be lifted to any desired height and the lifting forks 19 and 20 rotated by means of the hydraulic cylinder 34 to partially or completely dump its contents. Upon rotating the lifting forks downwardly, the pallet halves 46 are rotated on the frame 50 so as to permit the contents of the container to flow through the open container bottom.

The lifting forks 19 and 20 need be raised only sufficiently to permit the pallet halves to swing to partially or fully opened position, thus minimizing the distance which the contents of the container must drop. This is of particular utility in the handling of fruits and vegetables which are easily bruised and damaged and in the handling of fragile articles which might be damaged or broken by pouring from the top of the container. Moreover, it permits the use of a cheaper, lighter weight container than would otherwise be necessary if the container were to be rotated about a horizontal axis to pour the articles from the top of the container as in certain lift fork designs.

If a more substantial pallet and container is desired, the pallet and container may be made into a unitary sheet metal structure as indicated in FIGURE 9. In this structure, the pallet halves 59 have slots 60 for receiving the lifting forks 19 and 20 and are hinged to the lower edges of two opposite sides of the container portion 61. In effect, the pallet halves 59 form the flaps of a bottom dump container.

I claim:

1. A fork lift device comprising a pair of parallel lifting forks lying in a generally horizontal plane, each of the lifting forks being mounted for rotation on an axis located a short distance laterally beyond the outside surface thereof, means for rotating said lifting forks between the horizontal and a position extending downwardly from its axis; and a bottom dump container having a pair of parallel vertical walls and a pair of bottom halves hinged one to the lower edge of each side wall, the lifting forks extending parallel to the hinged connection between the bottom halves and side walls, and the axes of the lifting forks coinciding generally with the axes of said hinged connection of the container.

2. A fork lift device, comprising a pair of parallel, flat lifting forks lying in a common, generally horizontal plane, a support for the forks, means mounting each of the forks on the support for rotation about an axis extending longitudinally of the forks and located a short distance laterally beyond the outside surface of the forks, a linkage interconnecting the lifting forks, and a hydraulic cylinder extending between the support and said linkage for controlling simultaneous rotation of each fork on its axis between the horizontal and a generally vertical plane.

3. A fork lift device and bottom dump container as claimed in claim 1, in which the means for rotating the lifting forks comprises a linkage interconnecting said forks and a hydraulic cylinder for operating said linkage to simultaneously rotate the forks.

4. A fork lift device and bottom dump container as claimed in claim 3, in which the lifting forks are mounted for rotation on a vertical movable carriage and the hydraulic cylinder is mounted on the carriage.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Thomas et a1. 294-71 Mourer 294-71 French 294-71 Miller 220-29 Dempster 214-77 Schroeder 214-652 Lilienfeld 248-120 Seagraves et a1 214-653 Gerhardt 214-653 Ulinski 214-653 Ehmann 214-653 6 5/ 1956 Cirillo 214-651 8/ 1959 Bishop 220-29 8/1961 Ulinski 214-653 1/1962 Bergstrom 214-653 X 5/1963 Summers 214-653 5/1963 Hunziker 214-653 FOREIGN PATENTS 4/ 1954 Germany. 7/ 1950 Great Britain.

HUGO O. SCHULTZ, Primary Examiner.

MORRIS TEMIN, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,217,912 November 16,. 1965 Charles E: McKeon It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 72, for "vertical" read H vertically Signed and sealed this 2nd day of August 1966.:

(SEAL) Attest:

ERNEST W. SW'IDEB Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

2. A FORK LIFT DEVICE, COMPRISING A PAIR OF PARALLEL, FLAT LIFTING FORKS LYING IN A COMMON, GENERALLY HORIZONTAL PLANE, A SUPPORT FOR THE FORKS, MEANS MOUNTING EACH OF THE FORKS ON THE SUPPORT FOR ROTATION ABOUT AN AXIS EXTENDING LONGITUDINALLY OF THE FORKS AND LOCATED A SHORT DISTANCE LATERALLY BEYOND THE OUTSIDE SURFACE OF THE FORKS, A LINKAGE INTERCONNECTING THE LIFTING FORKS, AND A HYDRAULIC CYLINDER EXTENDING BETWEEN THE SUPPORT AND SAID LINKAGE FOR CONTROLLING SIMULTANEOUS ROTATION OF EACH FORK ON ITS AXIS BETWEEN THE HORIZONTAL AND A GENERALLY VERTICAL PLANE. 